In the conventional residential network, Local IP Access (LIPA) is supported only in the situation where Local-Gateway (Local-GW) is collocated with a Home evolved Node B (HeNB). FIG. 1 is a diagram illustrating architecture of a network supporting LIPA but not supporting Session Continuity.
Referring to FIG. 1, the HeNB is also referred to as Closed Subscribed Group (CSG) cell which permits the access of only the UEs preregistered with a specific group (i.e. CSG). The CSG cell may be a home cell deployed within a small area such as personal residential area or company/local area network cells deployed within a wide area for a company or specific organization. A femto cell eNB 150 according to an embodiment of the present disclosure provides only the UE registered therewith with the mobile communication service and broadcasts the identifier of a predetermined group registered therewith, i.e. CSG ID, in a System Information Block (SIB). The LGW (HeNB GW) is responsible for establishing a connection between the SGW and HeNB. The UE may connect to the core network via the HeNB.
The Mobility Management Entity (MME) manages the UE in idle mode and selects Packet Data Network (PDN) gateway and serving gateway. The MME also processing bearer signal generated by the UE the Serving Gateway (SGW) acts as mobility anchor in handover between eNBs or between 3GPP wireless networks. The Packet Data Network Gateway (PGW) allocates IP address to the UE, performs packet data-related function of the core network, and acts as mobility anchor in handover between 3GPP and non-3GPP wireless networks. The PGW also determines the bearer band provided to the subscriber and is responsible for packet data forwarding and routing function.
In the enterprise network structured as shown in FIG. 1, one or more HeNBs may exist in the same enterprise network and, in this case, it is required to support session continuity when the UE moves between HeNBs in the same enterprise network.